Watch the Pea – AR5 (ZOD) Chapter 10

As CA readers are aware, key findings of Santer et al 2008 do not hold using updated data. Ross and I submitted a comment to IJC showing this. The comment was rejected twice, with one of the reviewers (as in the case of the comment on Steig et al) being a Santer coauthor (who was not identified to us as such). Ross eventually managed to get similar results published in another journal.

Jean S points out in a comment on the Steig thread that our findings were completely misrepresented by IPCC AR5 (ZOD) chapter 10 (also the source of disinformation about Steig).

Our article stated that there was a statistically significant difference between models and observations in the tropical troposphere. Instead of citing our articles as rebutting Santer’s assertions, IPCC cites us as endorsing Santer’s false assertions:

The claim by Douglass et al. (2008) that modeled and observed trends in the tropical troposphere for the period from 1979 to 1999 are significantly different is contradicted by Santer et al. (2008) and McKitrick et al. (2010). The findings of Santer et al. (2008) are based on analyzing updated radiosonde and satellite datasets, considering observed and simulated trend uncertainties due to natural variability. Santer et al. (2008) also provide evidence based on synthetic data that the consistency test applied by Douglass et al. (2008) leads to incorrect conclusions.

They go on to make the following absurd statement:

Taking these studies together, we conclude, that apparent differences between tropical free tropospheric temperature trends in models and observations and differential warming in the tropics over the period 1979–1999 are unlikely to be statistically significant after fully accounting for observational uncertainties.

Watch the pea. The issue with Santer was that key results fell apart over the longer period of 1979-2009 (or 2010 or 2011) as opposed to the 1979-1999 period. As noted above, realclimate spoke out strongly against Courtillot’s analysis which didn’t use up-to-date data. Pierrehumbert alleged that such analysis was dishonest. Why should different standards apply when employed by IPCC chapter 10?

21 Comments

Have you recently walked through the implications of this for current considerations? I have formed a harshly negative opinion of Santer’s performance, partially based on this incident. However, If his error continues to be perpetuated through the literature, what are the ramifications for maintaining a good view of the issues?

Although Santer has received many laurels, his actual corpus over the past decade has been very thin. He’s been arguing for years (mostly against Douglass and Christy) that there is no “statistically significant” difference between models and observations. Their dispute makes the Mann dispute seem recent.

When I went to look for the realclimate post in which they vehemently condemned Courtillot’s use of outdated data, I discovered, much to my surprise, that it had been deleted from realclimate. ( A record is, of course, at Wayback machine here.)

It was deleted some time this year. I wonder why.

Steve: The link nomenclature was changed earlier this year; the post was not deleted. It looks like a RC reorganization of filenames caused the apostrophe to be rendered differently after June 2011 or so.

Steve: They must have restored it. I had a link to this post from CA and the link failed earlier today.

Jean S: I can confirm what Steve is saying. When I clicked the link in the end of Part I, it took me straight to the front page of RC. You can confirm this behaviour also from the Wayback Machine – the last snapshot (July 1) is the frontpage of RC at the time.

The cretins really have gone the full Skeptical Science route. Baseless statements, machine-gunning pseudoreferences and now the rewriting of history. Well if the AGU is in the hands of an English Major no wonder the IPCC follows the rules dictated by a cartoonist.

The IPCC process is as relevant for science as for policy. IRrelevant that is.

Hi Glenn — I hope the slow reviewer is not one that I suggested! Sorry if it is. I’m not
sure what Ben Santer expects you to do about it at this stage; I guess you didn’t expect
such a lengthy article… I’ve not seen it, but Phil Jones told me it ran to around 90
pages! Hope all’s well in NZ. Tim
At 03:32 06/05/2008, Ben Santer wrote:

Dear Glenn,
This is a little disappointing. We decided to submit our paper to IJoC in order to
correct serious scientific errors in the Douglass et al. IJoC paper. We believe that
there is some urgency here. Extraordinary claims are being made regarding the scientific
value of the Douglass et al. paper, in part by co-authors of that paper. One co-author
(S. Fred Singer) has used the findings of Douglass et al. to buttress his argument that
“Nature not CO2, rules the climate”. The longer such erroneous claims are made without
any form of scientific rebuttal, the more harm is caused.
In our communications with Dr. Osborn, we were informed that the review process would be
handled as expeditiously as possible. Had I known that it would take nearly two months
until we received a complete set of review comments, I would not have submitted our
paper to IJoC.
With best regards,
Ben Santer
???@auckland.ac.nz wrote:

05-May-2008
JOC-08-0098 – Consistency of Modelled and Observed Temperature Trends in the Tropical
Troposphere
Dear Dr Santer
I am hoping to have the remaining set of comments with 2 weeks of so. As soon as I have
these in hand I will pass them onto to you.
Best,
Prof. Glenn McGregor

“Get the picture? By snipping out just the last bit of the curve and normalizing to unit standard deviation, Courtillot inflates the variability and makes the fit look better than it would be if the full data set were used.”

I think it’s very important to separate as much as possible the scientific and political responses. Regarding the political aspect, there are few certainties in life, but the fact that no matter how rationally and exhaustively we respond as scientists, the contrarians are going to come back at us with half-truths, distortions, cherry-picking of facts, etc. is probably as certain as it gets. So I suggest that we
carefully consider 2 separate activities:

(1) the political response to the recent contrarian paper(s) (Douglass et al, etc)

OK, let me get this straight. The IPCC cites one pager but ignores it’s rebuttal. Then the IPCC cites another paper in order to support a conclusion it is seeking, but this paper has been rebutted by a paper that has updated data, yet presents the rebuttal as support for the original paper.

I suppose that’s what they mean when they write about doing science for the ’cause’.

This post reminds me that I had meant to put up a notice that our Corrigendum to MMH10 has been published here. Chad found an error in the GISS GCM data and RSS & RICH revised their data, and when we re-did the calculations our results came out a bit stronger. Among other things, using the corrected data the 1979-1999 model/obs differences are now significant at the 10% level, and at the 1% level for 1979-2009. So the IPCC quote is wrong as stated. And of course it is an obvious half-truth, distortion and cherry-pick, since they ignore the more important issue of the 1979-2009 difference. All MSU and balloon series are significantly below the GCM average over 1979-2009, individually and jointly.

There are some fun quotes in the CG2 emails about ‘increased probability’ of failing confidence intervals as time goes on. I don’t have them handy but the abuse of stats looks more like incompetence than I’ve ever understood before.

[…] written a couple of posts on the blatant bias in the AR5 draft, one of the most obvious being the suppression of his and McKitrick’s peer-reviewed paper demolishing a Santer defense of climate models. As […]